Analyte sensor introducer and methods of use

ABSTRACT

Method and apparatus for providing an introducer for transcutaneous placement of at least a portion of an analyte sensor through the skin of a patient is provided.

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 11/216,932 filed Aug. 30, 2005, now U.S. Pat. No. 7,731,657,entitled “Analyte Sensor Introducer and Methods of Use”, the disclosureof which is incorporated herein by reference for all purposes.

BACKGROUND

The present invention relates to data monitoring systems. Morespecifically, the present invention relates to method and apparatus forproviding an analyte sensor introducer for transcutaneous placement ofan analyte sensor into a patient for use in analyte monitoring systemsincluding glucose monitoring systems.

Glucose monitoring systems generally include a sensor such as asubcutaneous analyte sensor for detecting analyte levels such as glucoselevels, a transmitter (such as an RF transmitter) in communication withthe sensor and configured to receive the sensor signals and to transmitthem to a corresponding receiver unit by for example, using RF datatransmission protocol. The receiver may be operatively coupled to aglucose monitor that performs glucose related calculations and dataanalysis such as for example, trend analysis, data management andmedical treatment planning and management.

The transmitter may be mounted or adhered to the skin of a patient andalso in signal communication with the sensor, at least a portion ofwhich may be implanted into the skin of the patient. Generally, thesensor is configured to detect and measure the glucose levels of thepatient over a predetermined period of time, and the transmitter isconfigured to transmit the measured glucose levels over thepredetermined period of time for further analysis. To initially set upthe sensor so that the sensor contacts and electrodes are in fluidcontact with the patient's analyte fluids, it is important to properlyinsert the sensor wholly or partially through the patient's skin andsecurely retain the sensor during the time that the sensor is configuredto detect analyte levels. In addition to accurate positioning of thesensor through the skin of the patient, it is important to minimize thelevel of pain associated with the insertion of the sensor through thepatient's skin.

In view of the foregoing, it would be desirable to have a sensorintroducing mechanism including sensor introducer for accurate and easyinsertion of the sensor through the skin of a patient or otherwise toproperly position the sensor, e.g., transcutaneously, so that the sensormay be configured to detect analyte levels of the patient. Also, itwould be desirable to have a method and apparatus to have a sensorintroducing mechanism that places the sensor at least partially throughthe skin of the patient with ease and relatively little pain.

SUMMARY OF THE INVENTION

In one embodiment, there is provided an analyte sensor introducerconfiguration and methods of use which provide reducedinsertion/extraction force through the skin of the patient therebyreducing the trauma to the patient's skin. In this manner, in oneembodiment, the puncture through the skin of the patient can bemaintained relatively small, which in turn, results in less bleeding andbruises to the patient's skin, allowing for a faster healing time.

In a further embodiment of the present invention, the introducer isintegrated into the housing of an analyte sensor inserter and a mountingunit of a sensor control unit, or a base housing which is configured toreceive a data transmitter (or a transceiver). As such, a single devicewhich incorporates the sensor insertion mechanism as well as providingthe support structure for mounting the transmitter to a patient isprovided. The data transmitter in one embodiment is configured forelectrical communication with the sensor, where the sensor is configuredto detect the patient's analyte level, and the transmitter configured totransmit (wirelessly or otherwise) to a monitoring unit such as aglucose monitor unit or an insulin pump.

In this manner, in accordance with the various embodiments of thepresent invention, the sensor may be introduced through the skin of thepatient for accurate transcutaneous placement while lessening the painto the patient during the sensor placement process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a perspective view of an analyte sensor introducer inaccordance with one embodiment of the present invention;

FIG. 2 is a detailed view of the shaft portion of the analyte sensorintroducer shown in FIG. 1 in accordance with one embodiment of thepresent invention;

FIG. 3 illustrates a perspective view of an analyte sensor introducer inaccordance with another embodiment of the present invention;

FIG. 4 is a detailed view of the shaft portion of the analyte sensorintroducer shown in FIG. 3 in accordance with another embodiment of thepresent invention;

FIG. 5 illustrates a perspective view of an analyte sensor introducer inaccordance with a further embodiment of the present invention;

FIG. 6 is a detailed view of the shaft portion of the analyte sensorintroducer shown in FIG. 5 in accordance with a further embodiment ofthe present invention;

FIG. 7 illustrates an analyte sensor introducer integrated with thetransmitter mount housing with a drive mechanism for placement on theskin of a patient in accordance with yet another embodiment of thepresent invention;

FIG. 8 illustrates the introducer integrated with the transmitter mounthousing of FIG. 7 in pre-deployment position in accordance with yetanother embodiment of the present invention; and

FIG. 9 illustrates the introducer integrated with the transmitter mounthousing of FIG. 7 after sensor deployment position in accordance withyet another embodiment of the present invention.

DETAILED DESCRIPTION

FIG. 1 illustrates a perspective view of an analyte sensor introducer inaccordance with one embodiment of the present invention. Referring tothe Figure, there is provided an introducer 100 having a body portion101 and a shaft portion 105. The shaft portion 105 includes asubstantially relatively sharp edge segment 103 which is configured tofirst contact the skin of the patient during the placement of theintroducer through the patient's skin for transcutaneous placement of ananalyte sensor 110. As shown, the sensor 110 is configured to beretained within the shaft portion 105 and held in position during thesensor 110 insertion process through the patient's skin by thesubstantially hollow cylindrical shape of the shaft portion 105 as shownin the Figure.

Referring to FIG. 1, the tip of the analyte sensor 110 is retained atthe edge segment 103 of the introducer 100 during the placement of thesensor 110 transcutaneously through the patient's skin. It should benoted that the edge segment 103 of the introducer 100 is configured tofirst pierce through the patient's skin, and at substantially the sametime, guide the retained sensor 110 maintained in the shaft portion 105of the introducer 100 through the pierced skin of the patient. When thesensor 110 is placed at the desired location under the skin, theintroducer 100 is configured to be retracted from the patient, leavingthe sensor 110 in place. More specifically, during the introducerremoval process from the patient, a radial configuration 104 of theshaft portion 105 is configured to guide the removal of the introducer100 from the pierced skin.

FIG. 2 shows a detailed view of the shaft portion of the analyte sensorintroducer shown in FIG. 1 in accordance with one embodiment of thepresent invention. In further embodiments, the shaft portion 105 mayhave a ribbed configuration so as to provide additional strength duringthe insertion and retraction of the introducer through the skin of thepatient. Moreover, as shown in FIGS. 1 and 2, the shaft portion 105 ofthe introducer 100 includes a substantially longitudinal slit opening102 which is provided to allow the introducer 100 to be completelyde-coupled from the sensor 110 retained within the shaft portion 105during the placement thereof, so that the introducer 100 may be removedcompletely from the patient, while leaving in place the sensor 110.

In this manner, in one embodiment of the present invention, theintroducer 100 may be configured to reduce the insertion and extractionforces through the patient's skin, thus reducing trauma to the skin. Bymaintaining a relatively small skin puncture, it is possible to reducethe amount of potential bleeding during the skin piercing process fortranscutaneous sensor placement, and likewise result in less bruisingand also faster healing.

As described above, in one embodiment of the present invention, theanalyte sensor is positioned within the substantially hollow shaftportion 105 of the introducer 100 such that the edge segment 103 of theintroducer 100 guides the sensor 110 into and through the skin puncture.In one embodiment, the edge segment 103 may be sharpened and polished tofacilitate a smooth puncture and a clean cut through the patient's skin.Moreover, the radial configuration 104 of the shaft portion 105 asdiscussed above provides a transition when the introducer 100 exits thepuncture so as to allow for a smooth and relatively painless removal ofthe introducer from the patient.

FIG. 3 illustrates a perspective view of an analyte sensor introducer inaccordance with another embodiment of the present invention, and FIG. 4is a detailed view of the shaft portion of the analyte sensor introducershown in FIG. 3 in accordance with another embodiment of the presentinvention. Referring to FIGS. 3 and 4, introducer 300 includes a bodyportion 301 and a shaft portion 302, where the shaft portion 302includes a relatively sharp and tapered edge segment 303 as shown. Alsoshown in the Figures is a longitudinal opening 304 along the shaftportion 302 of the introducer 300 extending from the edge segment 303.

In this manner, in one embodiment of the present invention, the analytesensor 310 is placed along the hollow shaft portion 302 of theintroducer 300 such that the shaft portion of the sensor 310 is guidedby the edge segment 303 of the introducer 300 during the transcutaneousplacement of the sensor 310. Accordingly, the edge segment 303 isconfigured to first pierce the patient's skin and thereafter the sensor310 retained within the shaft portion 302 of the introducer 300 isintroduced through the patient's skin following the directional movementof the introducer 300.

As described above, the introducer in one embodiment may be configuredto substantially retain the sensor 310 and place the sensor through theskin of the patient so that the sensor 310 is easily and quickly guidedthrough the skin, minimizing the potential for the sensor 310 to deflectoff (and thus not penetrate) the skin during the insertion process. Thisis particularly guided in one embodiment by the edge segment 303 of theintroducer 300 as shown in the Figures above. Additionally, thelongitudinal slit opening 304 substantially parallel to the length ofthe shaft portion 302 of the introducer 300 is provided to allow theintroducer 300 to be removed completely from the patient while leavingthe sensor 310 in place after deploying the same under the skin.

Moreover, in accordance with the various embodiments, and assubstantially shown in the Figures described above, the introducerconfiguration is provided such that the amount of drag and frictionsduring the introducer introduction through the patient's skin isreduced, while the substantially hollow and cylindrical shaft portion ofthe introducer is configured to minimize the necessary force to deploythe introducer so that the sensor is properly placed through thepatient's skin, while the speed of the insertion and removal of theintroducer is also optimized for minimizing pain and skin trauma.

FIG. 5 illustrates a perspective view of an analyte sensor introducer inaccordance with a further embodiment of the present invention, whileFIG. 6 shows a detailed view of the shaft portion of the analyte sensorintroducer shown in FIG. 5 in accordance with a further embodiment ofthe present invention. Referring to the Figures, introducer 500 includesa body portion 501 and a shaft portion 502, where the shaft portion 502further includes a substantially sharp edge segment 503, an upper foldsegment 505 and a tab segment 504. In one embodiment, the upper foldsegment 505 is configured to substantially retain the sensor 510 withinthe shaft portion 502 of the introducer 500, while the tab segment 504is similarly configured to retain the sensor 510 within the shaftportion 502 so as to guide or maintain the position of the sensor duringthe insertion of the introducer 500 through the patient's skin.

More specifically, the shaft portion 502 is configured so as tosubstantially retain the portion of the sensor 510 that is to be placedunder the skin of the patient so as to be in fluid contact with thepatient's analyte. Moreover, the edge segment 503 of the introducer 500includes a substantially sharp and angled tip for piercing the patient'sskin. Indeed, the edge segment 503 of the introducer 500 is sharp andtapered to facilitate skin piercing while minimizing skin trauma. Inthis manner, it is possible to minimize the size of the skin wound atthe piercing site where the introducer 500 is placed through the skin,and thus, the patient will likely experience a faster healing time.

Referring back to FIGS. 5 and 6, it can be seen also that the shaftportion 502 is configured so that the sensor 510 that is retainedsubstantially within the shaft portion 502 during the insertion of theintroducer 500 through the skin, can be completely de-coupled andseparated from the sensor 510 when the sensor 510 is placed in its finalposition. In this manner, the introducer 500 may be removed from thepatient, while at least a portion of the sensor is retained in fluidcontact with the patient's analyte so as to monitor its levels, forexample.

FIG. 7 illustrates an analyte sensor introducer integrated with thetransmitter mount housing with a drive mechanism for placement on theskin of a patient in accordance with yet another embodiment of thepresent invention. Referring to the Figure, there is provided atransmitter mount 702 configured to receive or mount with a transmitter701. The transmitter mount 702 in one embodiment is configured to couplewith a drive mechanism 703 that may optionally be reusable. Thetransmitter mount 702 housing may be further configured to integrate aspring 706 which, in conjunction with the drive mechanism 703, isconfigured to provide insertion and/retraction force for introducing thesensor 704 and the sensor introducer 705. Referring back to FIG. 7, thetransmitter mount 702 in one embodiment also includes a sensor 704 and asensor introducer 705 integrated within the housing of the transmittermount 702.

In operation, the patient in one embodiment arms (or cocks) the drivemechanism 703 to generate the sufficient inertial force needed to drivethe introducer 705 and the sensor 704 through the patient's skin. Morespecifically, in one embodiment, the introducer 705 and the sensor 704are provided in a fully assembled package within the transmitter mount702. Thus, when the patient wishes to place the sensor 704subcutaneously, the drive mechanism 703 is armed and the patient placesthe transmitter mount 702 on the surface of the patient's skin where thepatient wishes to place the sensor 704. Thereafter, the driver mechanism703 is operated to drive the introducer 705 and the sensor 704 throughthe skin of the patient.

In one embodiment, the drive mechanism may include spring biasedmechanism, magnetic force implementation, as well as a motor and gearcombination, or the like, so as to provide the necessary force forinserting the introducer 705 and the sensor 704, as well as to retractthe introducer 705. Furthermore, within the scope of the presentinvention, the drive mechanism 703 may be activated by using one or moreof an activation button, a lever, plunger, a switch, a knob or any typeof suitable activation mechanism that the patient may easily operate toactivate the drive mechanism 703.

Referring back to the Figures, FIGS. 8 and 9 illustrate the introducerintegrated with the transmitter mount housing of FIG. 7 inpre-deployment and post deployment positions, respectively, inaccordance with yet another embodiment of the present invention. Indeed,as shown in FIG. 9, after the sensor has been deployed and inserted intothe skin of the patient, the tip portion 901 of the sensor 704 ispositioned out of the housing of the transmitter mount 702 so as to betranscutaneously placed under the skin of the patient.

In this manner, in one embodiment of the present invention, the sensor704 may be substantially precisely guided through the transmitter mount702 and positioned at a specified depth under the patient's skin, e.g.,in the subcutaneous tissue. When the insertion is completed, the spring706 as shown in the Figures in one embodiment is configured to retractthe introducer 705 out of the patient, so as to be retained within thetransmitter mount 702. Thereafter, the drive mechanism 703 may beremoved from the transmitter mount 702 and may be reused for futuresensor insertion with one or more other sensors. Once the drivemechanism is removed, the transmitter 701 is placed in position andcoupled with the transmitter mount 702 so as to establish electricalconnection with the appropriate electrodes of the sensor 704 in order tobegin transmission of the detected analyte levels to a receiving devicesuch as a receiver/monitoring unit.

In the manner described above, in accordance with one embodiment of thepresent invention, such “on-board” insertion configuration of analytesensors eliminates the need for a sensor delivery unit (such as aseparate insertion device), and thereby reducing the associated materialcosts, weight, packaging, handling, as well as disposal thereof.Additionally, the number of steps that are necessary for the patient toperform to introduce and position the analyte sensor is reduced whichprovides significant advantages, especially in continuous monitoringsystems where the sensor typically requires replacement at apredetermined interval.

Moreover, in certain embodiments, the transmitter 701 may be integratedinto the transmitter mount 702 so as to provide a unitary piece ofconstruction. Such embodiments reduce the number of separate componentsand reduce the number of steps a user performs by omitting or minimizingthe steps of attaching or mounting a transmitter to the base portion.Additional detailed information on the detection, monitoring andanalysis of analyte levels are described in further detail in U.S. Pat.No. 6,175,752 entitled “Analyte Monitoring Device and Methods of Use”the disclosure of which is incorporated herein by reference for allpurposes.

In the manner described above, in accordance with one embodiment of thepresent invention, there is provided an introducer, comprising a bodyportion, and a shaft portion extending substantially from an edge of thebody portion, the shaft portion including a tapered end, the shaftportion configured to substantially retain a sensor, and further, wherethe tapered end is configured to guide the sensor through a skin layer.

In one embodiment, the shaft portion may be substantially hollow, andfurther, the shaft portion may include an opening substantially alongthe length of the shaft portion.

Additionally, the opening of the shaft portion may be configured to bewider than the width of the sensor such that the sensor may be displacedout of the shaft portion through the opening.

Further, the shaft portion may be configured to retain at least aportion of the sensor substantially subcutaneously when the shaftportion is removed from the skin layer.

In a further embodiment, the tapered end of the shaft portion may beconfigured to pierce the skin layer, and further, wherein at least aportion of the sensor is substantially retained within the shaft portionwhile the tapered end is piercing through the skin layer.

Moreover, when the tapered end of the shaft portion is transcutaneouslyintroduced to the skin layer, the sensor may be substantiallycontemporaneously transcutaneously introduced through the skin layer.

In one aspect, the sensor may include an analyte sensor, where theanalyte sensor includes a glucose sensor. In a further aspect of thepresent invention, the sensor may include other types of sensorsincluding, but not limited to short term or long term analyte sensors,blood glucose sensors, implanted electrochemical sensors, or the like.

Also, the analyte sensor may be in fluid contact with the patient'sanalyte.

A method of introducing a sensor in a further embodiment of the presentinvention includes aligning a tapered end of an introducer substantiallyonto a sensor insertion site of a patient, piercing the skin at thesensor insertion site of the patient with the tapered end of theintroducer, guiding a sensor with the introducer through the skin, andremoving the introducer substantially completely from the patient whilesubcutaneously retaining at least a portion of the sensor in thepatient.

In one embodiment, the guiding step may include the step ofsubstantially entirely retaining at least a portion of the sensor withina shaft portion of the introducer.

Moreover, the tapered end of the introducer may include a substantiallysharp edge segment configured to pierce the skin, where the sharp edgesegment of the tapered end may be substantially configured at an anglegreater than 45 degrees relative to the direction of the sharp edgesegment piercing the skin.

An introducer in a further embodiment of the present invention includesa body portion, and a shaft portion extending substantially from an edgeof the body portion, the shaft portion including a tapered end, theshaft portion configured to substantially retain an analyte sensor, andfurther, where the tapered end may be configured to guide the analytesensor through a skin layer such that at least a portion of the analytesensor is in fluid contact with an analyte of a patient under the skinlayer.

An analyte monitoring system in a further embodiment of the presentinvention includes a sensor, an introducer, and a transmitter, theintroducer including a body portion, and a shaft portion extendingsubstantially from an edge of the body portion, the shaft portionincluding a tapered end, the shaft portion configured to substantiallyretain the sensor, and further, where the tapered end is configured toguide the sensor through a skin layer, and the transmitter configured tooperatively couple to the sensor to transmit a data associated with adetected analyte level received from the sensor.

In a further embodiment, the system may also include a receiveroperatively coupled to the transmitter, the receiver configured toreceive the data from the transmitter. Moreover, the transmitter in oneembodiment may be configured to wirelessly transmit the data.

An inserter kit in accordance to still a further embodiment of thepresent invention includes a sensor, an introducer that includes a bodyportion, a shaft portion, and a drive mechanism, the shaft portionextending substantially from an edge of the body portion, the shaftportion including a tapered end, the shaft portion configured tosubstantially retain the sensor, and further, wherein the tapered end isconfigured to guide the sensor through a skin layer of a patient, andthe drive mechanism coupled to the body portion, the drive mechanismconfigured to drive at least a section of the shaft portion through theskin layer, and further, to retract the section of the shaft portionsubstantially completely out of the patient, where at least a portion ofthe sensor is placed subcutaneously when the section of the shaftportion of the introducer is retracted from the skin layer such that thesensor is substantially in fluid contact with the analyte of thepatient.

Various other modifications and alterations in the structure and methodof operation of this invention will be apparent to those skilled in theart without departing from the scope and spirit of the invention.Although the invention has been described in connection with specificpreferred embodiments, it should be understood that the invention asclaimed should not be unduly limited to such specific embodiments. It isintended that the following claims define the scope of the presentinvention and that structures and methods within the scope of theseclaims and their equivalents be covered thereby.

What is claimed is:
 1. A method, comprising: aligning a tapered end ofan introducer substantially onto a sensor insertion site by positioninga housing over the insertion site, the introducer coupled to a sensorand the housing and the sensor having a portion provided within thehousing; piercing a skin layer at the sensor insertion site with thetapered end of the introducer with a drive mechanism detachably coupledto the housing to provide insertion force to the introducer duringsensor insertion; guiding the sensor with the introducer through theskin layer, the introducer including a segment for limiting movement ofthe sensor when the sensor is guided through the skin layer; retractingthe introducer from the skin layer while subcutaneously retaining atleast a portion of the sensor under the skin layer; retaining theintroducer within the housing after retraction from the skin layer andsensor insertion through the skin layer; and detachably removing thedrive mechanism from the housing after the sensor is guided through theskin layer and the introducer is retained within the housing; whereinthe introducer includes a body portion and a shaft portion extendingsubstantially from an edge of the body portion, the shaft portionincluding a tapered end and a segment, the shaft portion retaining thesensor, and further, the tapered end guiding the sensor through the skinlayer during sensor insertion and the segment limiting movement of thesensor when the sensor is guided through the skin layer.
 2. The methodof claim 1, including maintaining the retracted introducer within thehousing.
 3. The method of claim 1, wherein the sensor includes ananalyte sensor.
 4. The method of claim 1, wherein guiding includessubstantially entirely retaining at least a portion of the sensor withinthe shaft portion of the introducer.
 5. The method of claim 1, whereinthe tapered end of the introducer includes a substantially sharp edgesegment configured to pierce the skin layer.
 6. The method of claim 5,wherein the sharp edge segment of the tapered end is substantiallyconfigured at an angle greater than 45 degrees relative to direction ofthe sharp edge segment piercing the skin layer.
 7. The method of claim1, wherein the sensor comprises a plurality of electrodes including aworking electrode, wherein the working electrode comprises ananalyte-responsive enzyme and a mediator, wherein at least one of theanalyte-responsive enzyme and the mediator is chemically bonded to apolymer disposed on the working electrode, and wherein at least one ofthe analyte-responsive enzyme and the mediator is crosslinked with thepolymer.
 8. An analyte monitoring system, comprising: a housing; asensor having apportion provided within the housing; an introducercoupled to the sensor and the housing, the introducer including: a bodyportion; and a shaft portion extending substantially from an edge of thebody portion, the shaft portion including a tapered end and a segment,the shaft portion retaining the sensor, and further, the tapered endguiding the sensor through a skin layer during sensor insertion and thesegment limiting movement of the sensor when the sensor is guidedthrough the skin layer, wherein the introducer, the housing, and thesensor are configured such that, after retraction of the introducer fromthe skin layer, the sensor remains inserted through the skin layer andthe introducer is retained within the housing; and a drive mechanismdetachably coupled to the housing to provide insertion force to theintroducer during sensor insertion, the drive mechanism detached fromthe housing after the sensor is guided through the skin layer and theintroducer is retained within the housing.
 9. The system of claim 8,further including a receiver operatively coupled to a transmitterdisposed in the housing, the receiver further configured to receive datafrom the transmitter.
 10. The system of claim 9, wherein the transmitteris configured to wirelessly transmit the data.
 11. The system of claim8, wherein the sensor is configured to monitor a level of an analyte.12. The system of claim 11, wherein after the sensor is guided throughthe skin layer, the sensor is in contact with interstitial fluid. 13.The system of claim 8, wherein the drive mechanism is reusable.
 14. Thesystem of claim 8, wherein the housing includes a spring coupleable tothe drive mechanism for providing the insertion force.
 15. The system ofclaim 8, wherein the drive mechanism is one of a spring biasedmechanism, magnetic force implementation, or a motor and gearcombination.
 16. The system of claim 8, wherein the drive mechanism isactivated using one or more of an activation button, a lever, a plunger,a switch, or a knob.
 17. The system of claim 8, wherein a transmitterunit is coupled to the housing after insertion of the sensor anddetachment of the device mechanism from the housing.
 18. The system ofclaim 17, wherein the transmitter unit is configured to transmit a levelof an analyte to a remote device.
 19. The system of claim 18, whereinthe remote device includes a receiver unit, monitoring unit and/or aninsulin pump.
 20. The system of claim 18, wherein the transmitter unitis configured for wireless communication.
 21. The system of claim 8,wherein the tapered end of the shaft portion is configured to pierce theskin layer.
 22. The system of claim 8, wherein the shaft portion issubstantially hollow.
 23. The system of claim 8, wherein the shaftportion includes an opening substantially along a length of the shaftportion.
 24. The system of claim 23, wherein the opening is configuredto be wider than a width of the sensor retained therein, such that thesensor may be displaced out of the shaft portion through the opening.25. The system of claim 8, wherein the sensor comprises a plurality ofelectrodes including a working electrode, wherein the working electrodecomprises an analyte-responsive enzyme and a mediator, wherein at leastone of the analyte-responsive enzyme and the mediator is chemicallybonded to a polymer disposed on the working electrode, and wherein atleast one of the analyte-responsive enzyme and the mediator iscrosslinked with the polymer.